Monday, October 31, 2016
Top-level professional football referees have enhanced visual perception, which means that they are better at spotting foul play and issuing the correct disciplinary action than lower-level referees, according to new research published in the journal Cognitive Research.
The researchers, from Belgium and the UK, had 39 football referees from the top and lower leagues in Belgium watch staged videos of fouls being committed from the point-of-view of a referee on the football pitch. Eye-tracking technology was used to assess their visual-search behaviour - that is the location that the referees' eyes fixated on and for how long.
Professor Werner Helsen, co-lead author from the University of Leuven in Belgium, said: "Our results show that elite referees have visual-search behaviour patterns that make them better at assessing foul play situations in football compared to lower league referees. When watching open play fouls being committed, elite referees spend more time fixating on the body part involved in the foul than other areas, suggesting that they are focusing on and interpreting the most crucial information within their visual display."
Visual-search behaviour is a primary skill utilised by professional athletes that enables them to coordinate perceptual-cognitive function with motor skills. Referees also rely heavily on visual-search behaviour in order to rapidly translate what they see into a correct decision based on the rules of the game. When asked to state if they thought the open-play foul committed deserved a disciplinary sanction (no card, yellow card or red card), elite referees made the correct decision with an accuracy of 61%, compared to 45% amongst lower level referees.
Dr Jochim Spitz, co-lead author, said: "Visual-search behaviour is an in-built cognitive function that can be improved through training and development. Understanding what it is exactly that makes elite referees able to make better decisions than lower-level referees could help devise training programmes specifically aimed at improving visual-search behaviour."
The video clips used in this study were filmed with the help of competitive football players who were tasked with simulating a variety of foul play scenarios including fouls in open play and from corner kicks. The action was filmed from approximately 10 meters away to mimic the proximity of a referee to the game in a real life situation. In order to make the simulations as natural as possible, no specific instructions were given to the players related to the type of foul that should be executed. A total of 20 videos were made, 10 open-play situations and 10 corner-kick situations, out of which three showed no foul play.
In the open-play and corner-kick scenarios, there was no difference between the numbers of locations that the referees focused on when watching the videos but, importantly, the elite referees did spend more time fixating on the contact zone between the attacker and the defender than the non-elite referees. Analysing the data collected from incorrect decisions made by referees, it was concluded that the fixation time plays an important role translating perceived incidents into a correct interpretation according to the 'Laws of the Game'.
Professor Werner Helsen added: "We can speculate from our results that the level of experience in elite referees is translated into long-term memory which allows their visual-search behaviour to be driven by acquired knowledge. Sub-elite referees on the other hand have less experience and seem to apply a more random control of visual fixation".
Example videos of foul play situations watched by the referees are available here: https://goo.gl/tXpNrW
Tuesday, October 25, 2016
Heading a football can significantly affect a player's brain function and memory for 24 hours, a study has found.
Researchers said they had identified "small but significant changes in brain function" after players headed the ball 20 times.
Memory performance was reduced by between 41% and 67% in the 24 hours after routine heading practice.
One of the study's authors suggested football should be avoided ahead of important events like exams.
The University of Stirling study was published in EBioMedicine.
It is the first to detect direct changes in the brain after players were exposed to everyday head impacts, as opposed to clinical brain injuries like concussion.
Researchers fired footballs from a machine designed to simulate the pace and power of a corner kick and asked a group of football players to head a ball 20 times.
The players' brain function and memory were tested before and after the exercise...
Wednesday, October 5, 2016
CREDIT: CHRISTIE CLANCY/PENN STATE
Major League Baseball players have become overwhelmingly overweight and obese during the last quarter century, say health researchers.
David E. Conroy, Penn State professor of kinesiology, and colleagues looked at 145 years of data on professional baseball players' body mass. The researchers found that the athletes' weight held steady for over 100 years, with the majority of them weighing in at what is considered "normal," -- i.e., with a body mass index (BMI) between 18.5 and 24.9.
However, around 1991 the average player's BMI began to rise, and over the last 25 years nearly 80 percent of players fall into the overweight or obese category with a BMI above 25. Obesity in the general U.S. population began to rise in the mid-1970s, according to the Centers for Disease Control and Prevention.
"Research exists that shows how having extra weight can help with certain aspects of baseball," said Conroy, also professor of human development and family studies. "The more force a batter can put into the ball, the further it will travel."
The researchers used the publicly available Lahman Baseball Database, where players' height, weight and age are recorded for their debut year in Major League Baseball. The data were self-reported, however Conroy points to the trend of players' increasing weight as informative -- and cause for some concern.
Conroy and colleagues report their findings today (Sept. 28) in Obesity Research and Clinical Practice.
"The data are observational, and raise more questions than they answer," cautioned Conroy. "BMI can be misleading, because it doesn't take body composition into account. What kind of pounds are the players adding? Are they mostly muscle or fat?"
The rise coincides with baseball's steroid era, and steroids are known to cause weight gain in some. But the rise also lines up with advances in sports science and nutrition, which have enabled athletes to better train and fuel, helping them build muscle and endurance -- which could lead to weight gain as well.
"These trends warrant further attention because of the potential for adverse long-term health consequences in this population and those who perceive them as role models for health and human performance," the researchers wrote.